--Theraclone Seeking Licensees and Strategic Alliances for the HIV
Program--

November 04, 2013 04:52 PM Eastern Standard Time

SEATTLE--(BUSINESS WIRE)--Theraclone Sciences, Inc., a therapeutic antibody discovery and
development company, today announced that collaborators published data
in the October 30th issue of Nature regarding an
antibody discovered by Theraclone and the International AIDS Vaccine
Initiative (IAVI) with significant potency and breadth against human
immunodeficiency virus (HIV). In the study, titled “Therapeutic efficacy
of potent neutralizing HIV-1-specific monoclonal antibodies in
SHIV-infected rhesus monkeys,” researchers demonstrated that a single
administration of PGT121 alone and in combination with an additional
monoclonal antibody potently reduced levels of simian HIV below
detection for weeks after dosing. Importantly, in this study, the virus
did not appear to develop resistance to PGT121.

“The discovery of broadly neutralizing antibodies, or bNAbs, such as
PGT121, which have the ability to target a large proportion of all major
circulating HIV subtypes, has rekindled the pursuit of antibodies in the
prevention and treatment of HIV and, according to the investigators in
the study, the findings encourage the investigation of monoclonal
antibody therapy for HIV-1 in humans,” said Kristine Swiderek, Ph.D.,
CSO of Theraclone Sciences.

As described in an earlier Nature publication in 2011, PGT121,
along with a large panel of other anti-HIV bNAbs, was discovered with
Theraclone’s proprietary I-STAR™ technology, which mines the human
memory B-cell repertoire of naturally-occurring human antibodies to
uncover those with exceptional biological activity. The result is a
broadly protective, fully human monoclonal antibody with therapeutic
potential to combat HIV infection.

In 2009, Theraclone and IAVI agreed to collaborate to use Theraclone’s
novel I-STAR technology for isolating potent monoclonal antibodies to
HIV that are broadly neutralizing from the blood of certain HIV-infected
individuals who had seemingly developed a protective immune response.
Such antibodies have the potential to neutralize many of the types of
HIV in circulation worldwide. IAVI retains rights to develop HIV
vaccines based on these antibodies, and Theraclone holds and controls
the rights to develop therapeutics based on these antibodies.

“This research highlights the power of our I-STAR technology to discover
potent antibodies from individuals that have developed a potent and
broadly protective immune response in historically difficult-to-treat
diseases,” said Clifford J. Stocks, Chief Executive Officer of
Theraclone. “At this time, we are seeking licensees and strategic
partnerships to capitalize on PGT121 and other HIV antibodies which
represent a significant opportunity for advancements in the treatment of
HIV.”

About Theraclone

Theraclone is a biopharmaceutical company focused on the discovery and
development of novel, monoclonal antibody therapeutics for diseases that
are devastating for patients and their families and which are a
significant threat to human health. Theraclone leverages its proprietary
antibody discovery technology, I-STAR™ (In-Situ Therapeutic Antibody
Rescue), to identify rare human antibodies that may be developed into
antibody product candidates that are potentially safer and more
effective than current therapies. Theraclone has a portfolio of
innovative antibodies in clinical and preclinical development targeting
serious medical conditions with a significant unmet medical need and a
primary focus on infectious disease and cancer, which include:

TCN-202 - a recombinant fully human monoclonal antibody for the
treatment and prevention of cytomegalovirus, or CMV infections

For more information about Theraclone, please visit www.theraclone-sciences.com.
On August 1, 2013, Theraclone and PharmAthene (NYSE MKT: PIP) announced
a definitive merger agreement.

About PharmAthene

PharmAthene is a leading biodefense company engaged in the development
and commercialization of next generation medical countermeasures against
biological and chemical threats. PharmAthene's current biodefense
portfolio includes the following product candidates:

Valortim® - a fully human monoclonal antibody for the
prevention and treatment of anthrax infection

In addition, in May 2013, the Delaware Supreme Court issued its ruling
on the appeal in our litigation with SIGA Technologies, affirming the
Court of Chancery’s finding that SIGA was liable for breach of contract,
reversing its finding of promissory estoppel, and remanding the case
back to the Court of Chancery to reconsider the appropriate remedy and
award of attorney's fees and expert witness costs in light of the
Supreme Court’s opinion. For more information about PharmAthene, please
visit www.PharmAthene.com.

Important Additional Information about the Proposed Merger

This communication is being made in connection with the proposed merger
involving PharmAthene and Theraclone. PharmAthene has filed with the
Securities and Exchange Commission (“SEC”) a Registration Statement on
Form S-4 (File No. 333-191055) ("Registration Statement") that includes
a definitive proxy statement/prospectus of PharmAthene and that also
includes a consent solicitation of Theraclone. The Registration
Statement was declared effective by the SEC on October 29, 2013. The
definitive proxy statement/prospectus/consent solicitation was mailed to
the stockholders of PharmAthene and the stockholders of Theraclone on or
about October 30, 2013. The proxy statement/prospectus/consent
solicitation contains information about PharmAthene, Theraclone, the
proposed transaction and related matters. STOCKHOLDERS ARE URGED TO
READ THE PROXY STATEMENT/PROSPECTUS/CONSENT SOLICITATION (INCLUDING ANY
AMENDMENTS OR SUPPLEMENTS THERETO) AND OTHER DOCUMENTS FILED WITH THE
SEC CAREFULLY IN THEIR ENTIRETY WHEN THEY BECOME AVAILABLE, AS THEY WILL
CONTAIN IMPORTANT INFORMATION THAT STOCKHOLDERS SHOULD CONSIDER BEFORE
MAKING A DECISION ABOUT THE MERGER AND RELATED MATTERS. In addition
to receiving the proxy statement/prospectus/consent solicitation by
mail, stockholders may also obtain the proxy
statement/prospectus/consent solicitation, as well as other filings
containing information about PharmAthene, without charge, from the SEC’s
website (http://www.sec.gov)
or, without charge, by contacting Stacey Jurchison at PharmAthene at
(410) 269-2610.

Participants in Solicitation

PharmAthene and its executive officers and directors may be deemed to be
participants in the solicitation of proxies from PharmAthene’s
stockholders with respect to the matters relating to the proposed
merger. Theraclone may also be deemed a participant in such
solicitation. Information regarding the proposed merger is available in
the definitive proxy statement/prospectus/consent solicitation that was
included in the Registration Statement declared effective by the SEC on
October 29, 2013 and that was first mailed to stockholders on or about
October 30, 2013. Information regarding certain interests that the
executive officers or directors of PharmAthene or Theraclone may have in
the proposed transaction is also set forth in the definitive proxy
statement/prospectus/consent solicitation.

No Offer or Solicitation

This communication is not intended to and does not constitute an offer
to sell or the solicitation of an offer to subscribe for or buy or an
invitation to purchase or subscribe for any securities or the
solicitation of any vote or approval in any jurisdiction in connection
with the merger or otherwise, nor shall there be any sale, issuance or
transfer of securities in any jurisdiction in contravention of
applicable law. No offer of securities shall be made except by means of
a prospectus meeting the requirements of Section 10 of the Securities
Act of 1933, as amended.

Forward-Looking Statements

Except for the historical information presented herein, matters
discussed may constitute forward-looking statements within the meaning
of the Private Securities Litigation Reform Act of 1995 that are subject
to certain risks and uncertainties that could cause actual results to
differ materially from any future results, performance or achievements
expressed or implied by such statements. Statements that are not
historical facts, including statements preceded by, followed by, or that
include the words “will,” “hopeful,” “designed,” “expect,”“objective” or
similar statements are forward-looking statements. Such statements
include, but are not limited to those referring to Theraclone’s clinical
development activities and the expected benefits of PGT121, the expected
completion and outcome of the merger and the transactions contemplated
by the merger agreement and related agreements. PharmAthene and
Theraclone disclaim any intent or obligation to update these
forward-looking statements. Risks and uncertainties include, among
others, failure to obtain necessary stockholder approval for the
proposed merger and the matters related thereto; failure of either party
to meet the conditions to closing of the transaction; delays in
completing the transaction and the risk that the transaction may not be
completed at all; failure to realize the anticipated benefits from the
transaction or delay in realization thereof; the businesses of
PharmAthene and Theraclone may not be combined successfully, or such
combination may take longer, be more difficult, time-consuming or costly
to accomplish than expected; operating costs and business disruption
during the pendency of and following the transaction, including adverse
effects on employee retention and on business relationships with third
parties; the combined company’s need for and ability to obtain
additional financing; risk associated with the reliability of the
results of the studies relating to human safety and possible adverse
effects resulting from the administration of the combined company’s
product candidates; unexpected funding delays and/or reductions or
elimination of U.S. government funding for one or more of the combined
company's development programs; the award of government contracts to
competitors; unforeseen safety issues; unexpected determinations that
these product candidates prove not to be effective or capable of being
marketed as products; as well as risks detailed from time to time in
PharmAthene’s annual report on Form 10-K and quarterly reports on Form
10-Q under the caption “Risk Factors” and in its other reports filed
with the SEC. Copies of PharmAthene's public disclosure filings are
available from its investor relations department and our website under
the investor relations tab at www.PharmAthene.com.